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I've watched an experiment where they compress a book with a hydraulic press, and the book appears to stay relatively intact under that pressure. It is mentioned that the hydraulic press has a 100-ton pressing capacity. You can watch it from minute 4 here:
https://www.youtube.com/watch?v=AmFe7ECTGQI&t=240s

I've also read somewhere that stacking books under a bed is a potential life-saving precaution if the building were to collapse in an earthquake; as books can withstand immense pressure and can create a pocket of space beside the bed where you can lie down. I've even found a photo depicting it:

enter image description here

A book doesn't deform or break like other solid materials. Of course, there can be tough metals that can stay intact under pressure/loading but a piece of paper is something flimsy. Why are books tough under loading even though they're composed of fragile components? How can we explain the physics behind this phenomenon?

I've also thought that it might be related to chemistry and the structural components of paper like cellulose; but it is mainly the stack of paper that makes a book sturdy.

Another factor that came to my mind is tensile strength but I'm not sure how to explain it within this context. It could be that the tensile strength increases when pieces of paper or books stack up.

ermanen
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A structure exhibits strength only by avoiding all possible easy failure modes.

A book loaded perpendicular to its pages doesn't buckle because lateral deformation would need to store a large amount of strain energy. (In contrast, a single page loaded lengthwise buckles easily because a large lateral deflection can arise with just a slight bending moment and slight stored strain energy. Even a book loaded parallel to the pages exhibits easy buckling because the pages can slide past each other as they laterally deflect. A book can shear easily as well, also because of this easy slippage.)

A book doesn't squash under uniaxial compression like a ductile metal because its molecular structure doesn't allow easy dislocation movement along slip systems in the manner of a polycrystal. In other words, the cellulose molecule isn't really susceptible to the atom-by-atom defect movement that occurs in an ordered lattice. Tearing pages is largely a matter of pulling the individual well-bonded molecules away from each other.

A book can resist crack propagation better than a single brittle block of wood because the crack comes to an end at the page surface and doesn't start up again easily at the next page. In this way, the pages act like laminations that provide toughness. (But books can be torn lengthwise because a crack runs through the length of each page.)

A book doesn't shatter because it's already mostly surface, when considering the individual pages. (Brittle failure is Nature's way of responding to stored strain energy by choosing as an alternative the energetic price of producing many new surfaces.)

Broadly, materials are strong and tough if most deformation or failure modes would consume energy, rather than release energy. Nature prefers lower-energy states.

Chemomechanics
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